I think you should call back and DEMAND to speak to management, and explain the exact behaviour of the person on the phone, while also explaining exactly what happend to your frog.
If management still brushes you off with the "no guaranteee policy", write them a couple of nice reviews on several sites, also be sure to drop this over the phone if your conversation leads to a dead end, the potential loss of more customers doesn't weigh up to a frog, and most management people know this.
I assume you don't frequent this store?